Light-emitting diodes (LEDs) are increasingly utilized in a variety of different lighting applications due to their lower energy consumption, longer lifetime, high physical robustness, small size, and fast switching times. FIG. 1 depicts a conventional LED package 100, in which an LED chip 105 is electrically and physically connected to a submount 110 on a surface-mount device (SMD) package 115. Wires 120 electrically connect submount contacts to contact pads 125 on the SMD package 115, and a plastic lens 130 is placed over the LED chip 105 to focus the light therefrom. As shown, a transparent liquid- or gel-based “glob top” encapsulant 135 is then disposed over all of the components within the SMD package 115 and cured to form a semi-rigid protective coating that is also transparent to light emitted by the LED chip 105. The encapsulant 135 typically has a lens-like shape to facilitate light emission from the packaged LED chip 105. LED package 100 also may feature one or more electrical contacts 140 that electrically connect the LED chip 105 to the submount 110, as well as an underfill 145. As shown, the underfill 145 may be disposed between the LED chip 105 and the submount 110 and provide mechanical support to the LED chip between the electrical contacts 140.
UV LEDs have shown great promise for applications such as medical therapy, sensors and instrumentation, and fluid sterilization. Unfortunately, the above-described conventional packaging is frequently unsuitable for UV LEDs, which may emit light having wavelengths less than 320 nm, less than 265 nm, or even less than 200 nm. As shown in FIG. 1, when the LED chip is a UV LED, the highly energetic UV light leads to deterioration and even formation of cracks 150 within the transparent encapsulant. Such cracking may lead to distortions or breaks in the bonding wires 120 or failure of the LED package 100 due to moisture introduced from the outside environment along the cracks 150. In addition, the UV radiation from UV LEDs can cause deterioration and even failure of the plastic lenses 130 that are typically utilized atop other (e.g., visible-light-emitting) LEDs. In view of these issues, there is a need for improved packaging schemes for UV LEDs that enable high reliability, mechanical robustness, and long lifetime for the packaged devices.